Insulation crushing solid wire clip terminal



Nov. 26, 1963 w. PFERD ETAL 3,112,147

INSULATION CRUSHING SOLID WIRE CLIP TERMINAL Filed March 26, 1962 l6 /5[3A /4A /7 v w. 'PFERD INVENTORS. K. H. POHL 0.5V. TYLER j emam ATTORNEYUnited States Patent 3,112,147 lNSULATlGN CRUSHKNG SOLID WERE CLIPTERMINAL William Pferd, Watehung, Karl-Heinz Pohl, Summit, and

Daniel W. Tyler, Middletown, NJ assignors to Bell Telephone LaboratoriesIncorporated, New York,

N.Y., a corporation of New York Filed Mar. 26, 1962, Ser. No. 182,560 13(Jlaims. (Cl. 339-97) This invention relates to electrical devices formaking connections between electrical conductors and more specificallyto connectors intended for connecting at least one electrical conductorwithout first removing the insulation therefrom.

The insulation crushing terminals included in the prior art are of suchstructure as to necessitate high tolerance specifications and expensivemanufacturing processes. In a typical method such terminals are made byfirst cutting a slot from a piece of metal and then bending the metal intwo directions into a bowed configuration with an armate cross section,thereby forcing the edges of the slot together to form the insulationcrushing edges. In addition to inhibiting mass production processes,high tolerances must be maintained to insure the mating of the edges ofthe slot at all points, thereby insuring electrical contact between theterminal and a conductor when the latter is forced between theinsulation penetrating jaws. The lack of mass production and the demandof high tolerances increase the price of such terminals, making themunattractive to prospective users.

Another method of making the jaws of insulation crushing terminalsincludes the shearing of a slit in a strip of material by bifurcatingthe strip so that one furcation is sheared away from the other in suchmanner that the elastic limit of the sheared material is exceeded. Onejaw must then be forced back into juxtaposition with the other,resulting once again in close tolerance demands to insure electricalcontact. This method is also limited to thin sectioned metal stripswhich further limit the size of the conductor that can be used inconjunction with the terminal. Too large a conductor will cause theterminal jaws to fail by excessive yielding, such failure being due tothe small cross section of the material and high stress levels inducedtherein. A further drawback of this method is that upon forcing one jawback into proximity to the other jaw, high levels of residual stress areinduced into the material, adversely affecting electrical properties andresulting in high failure rates due to excessive yielding of theterminal jaws when electrical conductors are forced therebetween.

An object of this invention is to facilitate the connection of insulatedwires to apparatus, or to each other, or both.

A more particular object is to connect insulated wires as indicatedwithout first removing the insulation from the wire at the zone ofconnection.

The novel terminal or connector of this invention is intended for use asa solderless, insulation penetrating terminal to be used in conjunctionwith insulated electrical conductors and Wires.

In accordance with the invention, we have provided a unique structurewherein more than one connection point is provided on each terminal anda multiplicity of terminals can be incorporated into a connecting board,plug or socket to greatly expand the possible number of electricalconnections and interconnections which can be made with such a device.

A feature of the invention is the provision of insulation crushing jawsor sheared edges that are effectively in contact with each other at allpoints when no wire is forced therebetween.

Another feature of the invention is the provision of a 3,112,147Patented Nov. 26, 1963 ice hooked receiving passage for temporaryplacement and holding of electrical conductors before they are forcedbetween the jaws of the insulation crushing terminal.

Another feature of the invention is the provision of a solderlessterminal of such novel structure that it may be stamped from a flatsheet of conducting material using well-known mass production processes.

Another feature of the invention is the provision of a terminal andblock structure wherein the upper surface of the block may be used as astop and as a cutting surface for removing excess wire.

Another feature of the invention is the provision of an electricalterminal having a plurality of common connecting points from whichconnecting boards, plugs, sockets and like devices incorporatingnumerous terminals can be made for connecting and interconnecting aplurality of electrical conductors.

In accordance with the preferred embodiment of the invention, a fiatstrip of electrically conducting material is bifurcated from near a freeend to a pre-punched elongated slot. This bifurcation is accomplished byshearing the material from one end of the elongated slot to a pointadjacent to the free end, being careful in the shearing process not toexceed the elastic limit of the material of the main body of theterminal. Due to such a precaution, when the shearing die is removed orretracted, the one furcation that has been sheared from its matingfurcation will return to its exact position before shearing, therebyforming a relatively zero-tolerance slit. The elongated slot near theintegral base section provides sufficient deflection of one arm as it issheared from the other arm to prevent forcing the terminal material nearthe integral base section into its inelastic range during the shearingprocess. This method of bifurcation under the elastic limit of theterminal material is made possible by the elongated slot of thestructure. When no electrical conductor or wire is forced between thetwo above-mentioned furcations or jaws, the sheared edges are inintimate contact with each other at all points, thereby insuring goodcontact when an electrical conductor is forced therebetween.

After shearing of the furcations, other dies cut and form a hookedreceiving passage providing a temporary electrical conductor holdingstructure.

In the invention, the above-mentioned terminals are mounted in aninsulating block, the upper surface of the latter being used as a stopto prevent the electrical conductors from being inserted too far intothe jaws and therefore into the elongated slot and also to provide ananvil surface against and upon which excess wire may be cut.

The invention will be more clearly understood from the followingdetailed description, when read in conjunction with the drawing, inwhich:

FIG. 1 is an elevation view of the terminal showing a plurality ofconnecting points;

FIG. 2 is an isometric view of a connector incorporating this uniqueterminal; and

FIG. 3 is an enlarged view of one connecting point of a terminal and theassociated mounting.

In the embodiment of the invention as depicted by the various figures,the structure of the terminal comprises a flat sheet of electricallyconducting resilient metal such as Phosphor bronze or the like. Near theintegral base section 11 of the terminal is an elongated slot 12 fromone end of which each connecting point is bifurcated into two arms 13and 14. The dimensions of the elongat ed slot 12 are important in thatthey determine the forces that the furcations will exert against eachother to rupture and penetrate the insulation of any electricalconductor that is forced therebetween.

The edges 13A and 14A of arms 13 and 14 are in intimale contact witheach other at all points whenever no electrical conductor is forcedbetween them. This is permitted by shearing the edges 13A and 14Awithout exceeding the elastic limit of the material in the integral basesection 11. Due to the elongated slot 12, one furcation may be shearedfrom the other without exceeding the elastic limit of the integral basesection 11 of the terminal. When the shearing die is retracted, the onefurcation that was sheared from the other will return to its originalposition, defining by edges 13A and 14A a relatively zero-toleranceslit.

One arm or furcation has a rounded end 15 and the other arm is longerand has a sidewise protrusion 16 extending partially over the roundedfree end 15. The hook or sidewise protrusion 16 forms a short conductorreceiving passage and opens into a notch, \/-shaped in this instance,which is bounded by the beveled side edges 17 and 18 of the arms 13 and14. The sidewise protrusion 16 along with the notch formed by thebeveled edges 17 and 18 constitutes a receiving passage in whichelectrical conductors can be temporarily placed and held, as shown inFIG. 2, before they are forced down between the sheared edges 13A and14A.

Electrical connectors may be made from the terminal by placing aplurality of terminals in a predetermined geometrical pattern in aninsulating block 2 as shown in HS. 2. The upper surface of the block 19(see FIG. 3) is located intermediate the ends of the sheared slit formedby the edges 13A and 14A. Electrical conductors are then forced betweenthe arms 13 and 1-.- of the terminal but are prevented by the uppersurface 19 of the insulating block 20 from being forced into theelongated slot 12 and therefore losing electrical contact. The uppersurface 19 of the insulating block 20 may also be used as an anvil forcutting off excess wire to complete a neat electrical connection, asshown in FIG. 3.

It is obvious that the invention is not limited to the specificstructure illustrated and that it may be employed in many ways toonumerous to mention by those skilled in the art. However, some of themore obvious ways are tube sockets, plugs and connecting devices. Suchuse is within the scope of the appended claims.

What is claimed is:

1. An insulation penetrating terminal for insulated electricalconductors comprising a fiat sheet of electrically conducting metalbifurcated from adjacent a free end to an integral base section at theother end and having an elongated slot portion, said furcations furtherhaving facing beveled side edges near their free ends defining a notch,one furcation having a rounded free end and the other being longer andhaving a sidewise protrusion extending partially over said rounded freeend to define therewith a short conductor receiving passage, one end ofsaid elongated slot portion being joined to said notch by a shearedslit, the latter having opposing edge portions for rupturing theinsulation of electrical conductors as they are forced therebetween.

2. An insulation penetrating terminal according to claim 1 wherein saidfurcations are spaced each from the other in a portion thereof adjacentto the integral base section to define said elongated slot.

3. An insulation penetrating terminal according to claim 1 wherein thenotch defined by the facing beveled side edges of the furcations isV-shaped.

4. An insulation penetrating terminal according to claim 1 wherein theshort conductor receiving passage opens toward one side of the terminaland also merges into the open end of the notch.

5. An insulation penetrating terminal according to claim 1 wherein theopposing edges of said sheared slit are in intimate contact with eachother at all points when no electrical conductor is therebetween.

6. An insulation penetrating terminal for insulated electricalconductors comprising a sheet of electrically conducting metalbifurcated from adjacent a free end to an integral base section at theother end, the furcations being spaced each from the other in a portionthereof adjacent to the integral base section to define an elongatedslot portion, said furcations further having facing beveled side edgesnear their free ends defining a V-shaped notch, said furcations havingrounded free ends forming a short conductor receiving passage opcninginto the open end of the V-shapcd notch, one end of said elongated slotportion being joined to said V- shaped notch by a sheared slit, thelatter having opposing edge portions for rupturing the insulation ofelectrical conductors as they are forced therebetween.

7. An insulation penetrating terminal according to claim 6 wherein atleast one of said free ends has a sidewise protrusion extending todefine a receiving passage, the latter opening toward one side of theterminal and also merging into the open end of the V-ohaped notch.

8. An insulation penetrating terminal according to claim 6 wherein saidsheet is a flat sheet of electrically conducting metal.

9. A connector for insulated electrical conductors comprising at leastone insulation penetrating terminal made of a flat sheet of electricallyconducting metal bifurcated from adjacent a free end to an integral basesection at the other end, the furcations being spaced each from theother in a portion thereof adjacent to the integral base section todefine an elongated slot portion, said furcations further having facingbeveled side edges near their free ends defining a V-shaped notch, onefurcation having a rounded free end and the other being longer andhaving a sidewise protrusion extending partially over said rounded freeend to define therewith a short conductor receiving passage openingtoward one side of the terminal and also merging into the open end ofthe V-shaped notch, one end of said elongated slot portion being joinedto said V-shaped notch by a sheared slit having opposing edge portionsfor rupturing the insulation of electrical conductors as they are forcedtherebetween, and a terminal block with said insulation penetratingterminals positioned in the terminal block in a predeterminedgeometrical pattern.

10. A connector according to claim 9 wherein said terminal block has anupper surface, said insulation penetrating terminals placed in saidterminal block in such manner that said upper surface is locatedintermediate the ends of said sheared slit thereby preventing anelectrical conductor from being forced down into the elongated slotportion of the insulation penetrating terminal.

11. A connector according to claim 10 wherein said terminal block is ofinsulating material for preventing electrical contact between theinsulation penetrating terminals.

12. A method for manufacturing insulation penetrating electricalterminals comprising in step by step progression a blanking processwherein the rough outside shape of the terminal is formed, a punchingprocess wherein each connecting point of the rough terminal has anelongated slot punched near an integral base section, a shearing processthat bifurcates each connecting point on a line from one end of thepre-punched elongated slot to a spot adjacent a free end of theconnecting point; and a finishing process wherein the final details ofthe terminal are completed.

13. A method for manufacturing insulation crushing electrical terminalsaccording to claim 12 wherein the shearing process is completed withoutexceeding the elastic limit of the terminal material in the integralbase section thereby forming a relatively zero-tolerance slit byallowing the sheared furcations to return to their original positionsupon extraction of the shearing die.

No references cited.

1. AN INSULATION PENETRATING TERMINAL FOR INSULATED ELECTRICALCONDUCTORS COMPRISING A FLAT SHEET OF ELECTRICALLY CONDUCTING METALBIFURCATED FROM ADJACENT A FREE END TO AN INTEGRAL BASE SECTION AT THEOTHER END AND HAVING AN ELONGATED SLOT PORTION, SAID FURCATIONS FURTHERHAVING FACING BEVELED SIDE EDGES NEAR THEIR FREE ENDS DEFINING A NOTCH,ONE FURCATION HAVING A ROUNDED FREE END AND THE OTHER BEING LONGER ANDHAVING A SIDEWISE PROTRUSION EXTENDING PARTIALLY OVER SAID ROUNDED FREEEND TO DEFINE THEREWITH A SHORT CONDUCTOR RECEIVING PASSAGE, ONE END OFSAID ELONGATED SLOT PORTION BEING JOINED TO SAID NOTCH BY A SHEAREDSLIT, THE LATTER HAVING OPPOSING EDGE PORTIONS FOR RUPTURING THEINSULATION OF ELECTRICAL CONDUCTORS AS THEY ARE FORCED THEREBETWEEN.